1. Field of the Invention
This invention relates generally to improvements in wheeled vehicles of the type having an electric powered, motor in-wheel drive systems, and preferably applicable to hybrid power systems, for propelling the vehicle. In particular, the wheeled vehicle according to this invention includes a combined brushless DC linear induction motor (LIM) vehicle propulsion or other motor-driven propulsion system and a wheel-axle structure, which enables the wheelbase and tilt of the vehicle chassis to be dynamically changed during propulsion of the vehicle.
2. Related Art
Electric vehicles and drive systems for vehicles are known. Electrically powered vehicles (“EV's”) are similar to vehicles powered by an internal combustion engine and typically include a chassis for supporting the power system (i.e., the fuel cell, battery, etc.), a drive train and a suspension system, the suspension system connecting several axle and wheel assemblies to the drive train, and an arrangement for operatively connecting the battery in driving relation to the wheels. The EV is attractive in that the power unit therefor, in the form of a rechargeable battery pack, is environmentally clean (e.g., does not pollute the air during its operation) and its operation is very silent. However, the EV has met with market resistance in that the battery pack therefor is heavy—cutting down on the ability of the vehicle to accelerate rapidly, is large in size—restricting the amount of available space for transporting passengers or goods, and must be recharged frequently—cutting down on the length of the trip and/or limiting its use to short trips and/or restricting its use to large cities where recharging stations are available.
Electric drive systems are known, as illustrated by the circular induction motor wherein the rotational motion of a magnetic field with respect to rotor conductors causes a voltage to be induced in each, proportional to the magnitude and the velocity of the field relative to the conductors.
A particular variation of the traditional induction motor is the linear induction motor (LIM), essentially the circular induction motor opened out flat. The magnetic field, instead of rotating, sweeps across the flat motor face. The stator, usually known as the LIM, consists of a 3-phase winding in a laminated iron core. When energized from an AC supply a traveling wave magnetic field is produced. Swapping two phases can reverse travel. Current produced in the reaction plate (the equivalent of the rotor) by the stator traveling field create a secondary field. Desirably, the LIM can be used where unusual rotary drives are at a disadvantage, thereby eliminating mechanical transmissions, increasing reliability, where space is at a premium. Desirably, the LIM makes an ideal variable speed drive. It behaves like a magnetic clutch and gives soft start action.
A particular application of the LIM is in magnetic levitation whereby an apparatus rides on a cushion of opposing electromagnetic fields instead of on a hub or rail of steel to enable the apparatus to travel faster and more efficiently is known. For example, the magnetic levitation of a train is discussed by Scott Gourley in “Track to the Future”, believed published in Popular Mechanics (May 1998) and by Dr. Richard F. Post in “Maglev: A New Approach”, believed published in Scientific American (January 2000). Desirably, such apparatus provides “frictionless” systems that reduces energy requirements as well as wear on mating parts, thus minimizing down time to facilitate repairs.
Prior published U.S. Pat. Nos. 5,722,326; 5,847,480; and 5,455,221 to Post each disclose magnetic levitation arrangements, the disclosures of which are hereby incorporated by reference.
Further, in its current form, the motor vehicle incorporates numerous mechanical connections that are wasteful of energy and expensive to maintain and/or repair. Desirably, an improved motor vehicle would eliminate as much structure (e.g., the vehicle suspension, struts, drive train and its interconnection with the suspension and vehicle wheels) as possible without the loss of their specific functions.
In one particular aspect, the four-wheel system of a traditional vehicle would desirably be such that the user, or electronics of the vehicle control, could selectively change one or both of the vertical height of the vehicle chassis from the ground, or the wheelbase (i.e., point of contact with the ground distance) between the front and rear wheels of the chassis. Such adjustability would enhance the ability of the vehicle to truly be “all-terrain vehicle”.
Electronics and an on-board computer system would be used to continuously monitor and adjust the position of the vehicle wheels, both vertically and horizontally relative to the longitudinal axis of the vehicle. The computer system would receive a first signal from one vehicle wheel as it moves along the ground, compare the signal with a predetermined value, and transmit a second signal to that wheel to adjust the position of the wheel relative to the other three vehicle wheels. This “signal comparing” could be conducted simultaneously and continuously on all of the four vehicle wheels to thereby enable the vehicle to be dynamically tuned to the road upon which it is moving, such as by maintaining the vehicle chassis (or platform) in a horizontal plane.
It would be desirable to provide an electric drive system to propel a vehicle, such as an automobile, that incorporates the positive advantages of the LIM and Maglev systems without the disadvantages associated therewith.